1. Field
Embodiments relate to a plasmonic all-optical switch, and more particularly, to an all-optical switch for controlling light by using dielectric permittivity which varies depending on the existence of a pump light source, and a light control method using the same.
2. Description of the Related Art
Recently, techniques for dynamically controlling plasmon characteristics of a photoactive material have been developed and played very important roles such as data processing and transmitting and energy harvesting. In most optical devices, the propagation of a surface plasmon wave is determined by a refractive index of a metal surface or a dielectric substance adjacent thereto. If the dielectric permittivity of a dielectric substance can be controlled, it is possible to actively change plasmon characteristics of an entire system and manipulate a light propagation in a metallic nano-structure as desired. Through study activities on this, a new study field “active plasmonics” for controlling a propagation of light in a nano-structure having a size not greater than an optical wavelength has come to the fore.
Various methods have been proposed to control a plasmon mode in a nano optical device, for example a light control method using heat, a light control method using a gate voltage, a light control method using light, or the like. Most studies have used the light control method using a gate voltage. However, even though a surface plasmon electric field is strongly confined to a metal-dielectric interface with a width not greater than a wavelength, due to very weak coupling between the electric field and the light, a very high voltage and a long channel are required for light switching and modulation. Further, devices which have been studied so far have a slow switching time, and thus, are not suitable for the ultrahigh speed information communication era which requires data transmissions of several Gbit/s.